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Ronald R Krueger, Vinicius Silbiger De Stefano, Caio Meister; Analysis of Topography-Guided LASIK Treatment Planning Strategies. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5981. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Topography-guided LASIK (TG-LASIK) requires adequate planning strategies when manifest and topographically measured cylinder values differ in axis and magnitude. The purpose of this study is to describe and analyze the approach that led to a successful correction in patients submitted to TG-LASIK.
Two-hundred and fifty-six eyes undergoing TG-LASIK by a single surgeon from Feb 2016 to May 2017 were enrolled in this retrospective study at the Cleveland Clinic. All eyes were healthy, without previous refractive surgery, and had at least 4 good quality topographic maps. The corneal shape was captured with the Allegro Topolyzer, and coupled with the refraction to generate an ablation profile with the Allegretto Wave Eye-Q laser. The cylinder magnitude and axis of laser entry were decided by the surgeon, based on both the manifest and measured values, assisted by additional data from the Pentacam and the LADARWave aberrometer. All patients were followed at 1 day, 1 week and 3 months.
At 3 months, 95.7% achieved UDVA of 20/20 or better, while 81.4% were 20/15 or better. 25.6% (66 eyes) gained one or more lines of BCDVA. Among these eyes, measured and manifest axis differed by less than 15° in 59%, 15° to 30° in 18% and more than 30° in 23%. When it differed by at least 5°, the measured axis was treated in 79%, 67% and 73% of eyes, respectively. The magnitude of measured cylinder was the same as manifest (± 0.1 D) in 17% of eyes, greater in 68% and less in 15%. In eyes with greater measured cylinder, 75% were treated between manifest and measured with only 7% at full measured value. By contrast, when manifest was greater, 60% were treated at full measured value with 40% in between. Finally, patients that improved their vision had a statistically significant reduction in their astigmatic aberration and a smaller increase in both coma and total high order aberrations. Details are presented in Figure 1.
TG-LASIK can achieve better than glasses vision in more than a quarter of eyes. In eyes gaining a line of vision, the measured axis is treated in 75%. When the measured magnitude is greater, a value between the measured and manifest is chosen in 75% to avoid overcorrection. Greater astigmatic aberration correction with smaller coma and total RMS induction were all factors observed in the group that improved their postoperative BCDVA.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Comparison of each aberrometry measurement change between both groups.
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